Golf Ball Effect
11-24-2009, 04:12 PM
#21
11-24-2009, 10:39 PM
#22
^ That was kind of a weak comparison. That dude took a pair of heads that needed a rebuild, rebuilt them, did his mods and then bumped the compression up. He should have only did the mods to the head, that way we could find out exactly what numbers they gave him.
12-29-2009, 06:22 PM
#23
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here you go...it seems that you cant apply it just anywhere... its best applied in certain areas
now we gotta figure our where to put it i guess
http://www.williamsmotowerx.net/images/valve2.jpg
http://www.popularhotrodding.com/tec.../photo_10.html
http://www.popularhotrodding.com/tec.../photo_04.html
heres a aircraft forum in which differnt people kinda explain why they dont use it.. basically
http://www.airliners.net/aviation-fo...ad.main/51641/
vortex generators do the same and the cost of manufacturing
and most important shape!!!
Now back to the original question: Dimples in golf *****, trip wires and other methods are there to induce turbulent flow and turbulent boundary layers. That makes sense for bluff bodies only. Because sleek, aerodynamic bodies (like an airplane wing for example) keep the flow attached even if it is laminar, by being as gradual as possible in joining the flow back together. And laminar airflow causes less skin friction drag than turbulent one. So an airplane would not benefit from dimples or trip wires.
now we gotta figure our where to put it i guess
http://www.williamsmotowerx.net/images/valve2.jpg
http://www.popularhotrodding.com/tec.../photo_10.html
http://www.popularhotrodding.com/tec.../photo_04.html
heres a aircraft forum in which differnt people kinda explain why they dont use it.. basically
http://www.airliners.net/aviation-fo...ad.main/51641/
vortex generators do the same and the cost of manufacturing
and most important shape!!!
Now back to the original question: Dimples in golf *****, trip wires and other methods are there to induce turbulent flow and turbulent boundary layers. That makes sense for bluff bodies only. Because sleek, aerodynamic bodies (like an airplane wing for example) keep the flow attached even if it is laminar, by being as gradual as possible in joining the flow back together. And laminar airflow causes less skin friction drag than turbulent one. So an airplane would not benefit from dimples or trip wires.
12-30-2009, 12:23 AM
#24
01-02-2010, 07:59 PM
#25
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here you go...it seems that you cant apply it just anywhere... its best applied in certain areas
now we gotta figure our where to put it i guess
http://www.williamsmotowerx.net/images/valve2.jpg
http://www.popularhotrodding.com/tec.../photo_10.html
http://www.popularhotrodding.com/tec.../photo_04.html
heres a aircraft forum in which differnt people kinda explain why they dont use it.. basically
http://www.airliners.net/aviation-fo...ad.main/51641/
vortex generators do the same and the cost of manufacturing
and most important shape!!!
Now back to the original question: Dimples in golf *****, trip wires and other methods are there to induce turbulent flow and turbulent boundary layers. That makes sense for bluff bodies only. Because sleek, aerodynamic bodies (like an airplane wing for example) keep the flow attached even if it is laminar, by being as gradual as possible in joining the flow back together. And laminar airflow causes less skin friction drag than turbulent one. So an airplane would not benefit from dimples or trip wires.
now we gotta figure our where to put it i guess
http://www.williamsmotowerx.net/images/valve2.jpg
http://www.popularhotrodding.com/tec.../photo_10.html
http://www.popularhotrodding.com/tec.../photo_04.html
heres a aircraft forum in which differnt people kinda explain why they dont use it.. basically
http://www.airliners.net/aviation-fo...ad.main/51641/
vortex generators do the same and the cost of manufacturing
and most important shape!!!
Now back to the original question: Dimples in golf *****, trip wires and other methods are there to induce turbulent flow and turbulent boundary layers. That makes sense for bluff bodies only. Because sleek, aerodynamic bodies (like an airplane wing for example) keep the flow attached even if it is laminar, by being as gradual as possible in joining the flow back together. And laminar airflow causes less skin friction drag than turbulent one. So an airplane would not benefit from dimples or trip wires.
cylinder head runners now a days arent mirror polished at all because its been found that a somewht rougher finish promotes flow and/or velocity.
i understand it cant just be anywhere. it may work on a car or ball but not a plane. the thing is, where do we put engines? cylinder head porting has gone more towards the golf ball idea than the idea of a completely smooth surface.
01-02-2010, 08:33 PM
#26
A turbulent boundary layer is beneficial to delay flow separation and a low pressure wake. The benefits of a turbulent boundary layer are very geometry dependent. Something with smooth transitions, such as an airplane wing will see no benefit since there is no flow separation, but something with a less smooth transition, such as a ball, will. I think when we talk about internal flow such as inside an intake runner, or a pipe, or anything else, it is a bit more complicated. Given that VA is going to remain constant for a certain temperature and pressure, I think the important factor is how it affects the pressure drop through the intake runner. ... just kind of brainstorming right now
03-03-2010, 03:03 PM
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there is a shop round here called antivenom, and they used to have a swap program to send out your stock throttle body to a machine shop where these golf ball divets were cnc machined onto the surface, creating from 5 to ten hp dyno proven. it definitely looked cool. not sure if they still do this...
03-26-2010, 12:45 AM
#30
the finer you can get the fuel the better. the more surface area from more droplets, the better the burn the more energy you can extract AND its more complete as far as emissions.
also. this is semi sorta related but in a harley engine. so if you arent interested in my redneck ways stop here.
my dad has a harley with a S&S super G, and one of their intakes. well after observing how horrible the atomization was when i was tuning it and watching rain drop sized fuel droplets entering the intake.. i decided to modify the intake manifold in an attempt to increase atomization post carburetor. the intake tracts are very short, and basically split from the central source (carb) and then run 180 degrees apart (opposite directions to feed each of the cylinders in the Vtwin) to fill each cylinder. i took a sharpie and drew what you would imagine sound waves to look like along the bottom, concave proximal to the inlet, and convex distal to the inlet. and carefully cut grooves on the bottom half of the intake exactly symmetrical on both sides to create a similar effect to what you are describing, using a specific bit that was perfect for the job (i was able to cut at a consistant depth by allowing the mandrel to stop my cutting depth. no damage). and then i cleaned up the rest with an 80 grit sanding roll. (these engines really are pretty disappointing from an "engineered to perform" standpoint.)
in the intangibles, this modification excelled. my dad was/is thrilled. throttle response was better, power was better especially in the midrange (which matches his cams). it used to fall on its face really bad at only 5200 rpm from running out of air, but now it'll pull to nearly 5500. and fuel milage increased just over 2mpg avg. from any other time in its life. pretty cool stuff and welcome results on an engine not known for doing anything all that well except making noise.
also. this is semi sorta related but in a harley engine. so if you arent interested in my redneck ways stop here.
my dad has a harley with a S&S super G, and one of their intakes. well after observing how horrible the atomization was when i was tuning it and watching rain drop sized fuel droplets entering the intake.. i decided to modify the intake manifold in an attempt to increase atomization post carburetor. the intake tracts are very short, and basically split from the central source (carb) and then run 180 degrees apart (opposite directions to feed each of the cylinders in the Vtwin) to fill each cylinder. i took a sharpie and drew what you would imagine sound waves to look like along the bottom, concave proximal to the inlet, and convex distal to the inlet. and carefully cut grooves on the bottom half of the intake exactly symmetrical on both sides to create a similar effect to what you are describing, using a specific bit that was perfect for the job (i was able to cut at a consistant depth by allowing the mandrel to stop my cutting depth. no damage). and then i cleaned up the rest with an 80 grit sanding roll. (these engines really are pretty disappointing from an "engineered to perform" standpoint.)
in the intangibles, this modification excelled. my dad was/is thrilled. throttle response was better, power was better especially in the midrange (which matches his cams). it used to fall on its face really bad at only 5200 rpm from running out of air, but now it'll pull to nearly 5500. and fuel milage increased just over 2mpg avg. from any other time in its life. pretty cool stuff and welcome results on an engine not known for doing anything all that well except making noise.
If I remember correctly on one of the fancy mercedes benz commercials with that german dude they were showing how the bottom of there cars are now aerodynamic just like the top. They showed a quick clip of a smoke line in a tunnel on the bottom and im pretty sure I remember seeing dimples on the bottom of the car plating.
